Are you sure that encryption, not hashing, is what you need? I am not exactly sure what you are planning to do, but you can take a look at XTEA or TEA (Tiny Encryption Algorithm).
I have read on a previous comment in another story about "shorting bonds and longing stocks" but this was given as an example of a bad idea. Why is it so? If in the long term stocks outperform bonds wouldn't this actually be a good strategy for a long-term investor? Obviously the risks would be higher, but since it is over the long term it shouldn't matter, right?